Apparatus for forming a leno selvage, in particular for shuttleless looms, comprising an electric motor having a rotor are known from the prior art, wherein the rotor has at least two guide elements spaced apart from one another for the leno thread for forming the leno selvage with the corresponding weft threads. An apparatus is known from the patent specification DE 4405776, for instance, in which an electrically controllable actuating motor is provided which drives a selvage disk, wherein the selvage disk forms the rotor of the electrically controllable actuating motor. The stator itself is attachable to the loom by a support part, and indeed preferably in a free space before the first heddle shafts of the loom which are disposed between the longitudinal beams and the strands. Provision is made in detail in this respect that the leno disk which forms the rotor of the electrically controllable actuating motor has two openings for the leno threads, the openings being arranged opposite one another, as guide elements. This known rotary leno selvage of a loom now works such that it carries out a few dozen revolutions in one direction and in so doing binds off a weft thread after a respective one revolution. A full leno selvage is thus produced. On the side of the feed of the two leno threads, said leno threads are twisted in accordance with the number of revolutions of the selvage disk such that a reversal of the direction of rotation is indicated to cancel this twist, that is the leno disk consequently has to rotate in exactly the opposite direction. The number of revolutions in each direction must in this respect be the same on average over time. If no reversal of the direction of rotation were made, the leno threads would tear at some time due to the increasing tension as a result of the increasing twisting.
A similar rotary leno selvage having an electromagnetic drive is known from DE 197 33 261 C2, wherein this motor works in the manner of a servo motor. A measurement of the rotational angle for the purpose of detecting a defined angular position of the leno disk is provided to this extent to coordinate the rotation of the leno disk with the shed opening of the loom. This means that the leno disk carries out a continuous movement coordinated with the speed with respect to the stroke movement of the heddle shafts toward the shed opening or toward the shed closing of the loom.
A so-called propeller leno is now known from EP 839 219 B1. Such a propeller leno is characterized by two arms arranged diagonally opposite at the rotor of an electric motor and thus by a small moved mass so that, as is described in EP 1 019 571 B1, such a propeller leno is controllable independently of the movement of the heddle shafts. This means that the acceleration of the propeller leno is such that, at the time of the opening of the leno shed by the shafts of the loom, the arms of the propeller leno having the eyelets which are arranged at the end side and through which the leno threads run have already raised the shed. The propeller leno is thus controlled independently of the shaft. This means that it is ensured by the known propeller leno that at the start of the weft insertion by the leno selvage apparatus, the two leno threads are also in the shed opening and the leno threads are moved directly into the closed shed position after the end of the weft insertion. It is thus only important that the respective end position, that is shed open or shed closed, is achieved by the apparatus at the latest when the heddle shafts have adopted a corresponding position. This means that a movement procedure synchronous for every point in time between the movement of the rotor of the electric motor with the movement of the heddle shafts is not required.
It is additionally known to provide a so-called cutting lane in looms having long warp beams in the fabric. The fabric is divided in this respect, wherein two leno selvage apparatus are provided in the region of the cutting lane to prevent a rippling of the fabric in order to prepare a leno selvage at each side. The arrangement of one or more propeller lenos in the cutting lane has the disadvantage, however, that, because said propeller leno has a relatively wide construction, the cutting lane is correspondingly wide, which means that “fabric is lost”.